Alluvial Soils Delineation and Analysis for the Big Laurel Creek – Whitetop Laurel Creek Watershed
The data used for this analysis was obtained from the U.S. Geological Survey (USGS) Web Soil Survey (WSS), which “provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation Service (NRCS) and provides access to the largest natural resource information system in the world” located online at https://websoilsurvey.nrcs.usda.gov/app/.
The USGS Web Soil Survey allows for the delineation and creation of an area of interest (AOI) using a shapefile of watershed boundaries, in this case the Big Laurel Creek – Whitetop Laurel Creek watershed.
The shapefile used to create the AOI is the watershed shapefile delineated using the USGS’s StreamStats website ( https://streamstats.usgs.gov/ss/ ), which I described in a previous blog post Equipment Research and Useful Modeling Technologies for Watershed Analysis November 05, 2025 .
To create the AOI, use the “Create AOI from Shapefile” functionality under the “Import AOI” option under “Area of Interest” on the left side on the main landing page.
The shapefiles needed are the files ending in .shp, .shx,.prj, and .dbf.
Use the files named “globalwatershed” in the zip file downloaded from StreamStats,
but not use the files named “globalwatershedpoint”.
A screenshot of this step is,
Click the button “Set the AOI” when the files are uploaded. The resulting screen will display the delineated AOI as the blue cross hatched area as shown on the screenshot below,
For a watershed like the Big Laurel Creek – Whitetop Laurel Creek watershed that contains land area in multiple states, you will receive the error/warning (which should be closed to proceed).
Once the AOI is created ("set"), select the tab marked “Soil Map” to
generate the soil map of the watershed. (For the Big Laurel Creek – Whitetop Laurel Creek
watershed, the soil map created contains over 100 different soil types!)
For an in-depth soils report, select the “Shopping Cart (Free)” tab and name the file and then select the checkout button in the upper right corner of the display. After checking out, a pop-up window will appear offering two delivery options, “get now” or “download later”. I would recommend using the "download later" function which will send a link to the completed report to an email address that you specify. (The download link is valid for 10 days after checkout.)
Returning to the interactive soil map, you can select the tab “Soil Data Explorer” to research numerous topics on soils in general, the various soil types in the watershed, and many other subjects.
The most important sub tabs under the "Soils Data Explorer" tab in my opinion are “Suitabilities and Limitations for Use” and “Soil Properties and Qualities”. (Some functions may not be available because “The necessary data is not present in the underlying database”.)
For an example, if you selected “Flooding Frequency Class”
under “Water Features” of the “Soil Properties and Qualities” tab, and selected
the “View Rating”, the system creates a watershed soil map such as,
Zooming into the Whitetop Laurel Creek drainage of the Big Laurel Creek – Whitetop Laurel Creek watershed
that was discussed in the earlier floodplain analysis blog post, the map
show much greater detail as seen below,
If you selected ‘View Description” for the “Flooding Frequency Class”, the following descriptions for the different colors would be provided, which is,
Other examples of the data available under the “Soil Properties and Qualities” tab are “Drainage Class” and “Hydrologic Soils Group”, both under the heading “Soils Qualities and Features”.
These qualities are important for watershed management and potential improvements, for example creating and restoring wetlands.
For the Whitetop Laurel Creek
drainage of the Big Laurel Creek – Whitetop Laurel Creek watershed (which
allows for sufficient detail for viewing), these descriptions and ratings are,
Drainage Class
Hydrologic
Soils Group
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It is likely that you may receive this error warning,
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Two representative detailed alluvial soil maps in the Big Laurel Creek – Whitetop Laurel Creek watershed are,
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A complete assessment of the Big Laurel Creek – Whitetop Laurel Creek watershed alluvial soils reveal that the primary soil groups (listed as they are identified for sediment flowing downstream in the watershed) are:
- Map Unit Name: Atkins loam, 0 to 3 percent slopes, frequently flooded; Map Unit Symbol: 1
- Map Unit Name: Derroc cobbly sandy loam, 0 to 5 percent slopes, occasionally flooded; Map Unit Symbol: 12B
- Map Unit Name: Craigsville cobbly sandy loam, 0 to 5 percent slopes, frequently flooded; Map Unit Symbol: 3
- Map Unit Name: Speedwell loam, 0 to 3 percent slopes, occasionally flooded; Map Unit Symbol: 39A
- Map Unit Name: Atkins loam, 0 to 3 percent slopes, frequently flooded; Map Unit Symbol: 2A
- Map Unit Name: Pope fine sandy loam, 0 to 3 percent slopes, occasionally flooded; Map Unit Symbol: 4
Important findings are that all are alluvium derived from sandstone, limestone, shale, and/or quartzite and/or siltstone and/or metasedimentary rock, as expected for the Valley and Ridge and Blue Ridge physiographic regions.
In general, the soil groups are:
- Drainage class: Well Drained
- Hydrologic Soil Group: A.
The detailed description of each soil group is provided below.
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1—Atkins loam, 0 to 3 percent slopes, frequently flooded
Map Unit Setting
National map unit symbol: 2rjwp
Elevation: 1,080 to 3,760 feet
Mean annual precipitation: 35 to 51 inches
Mean annual air temperature: 50 to 55 degrees F
Frost-free period: 135 to 180 days
Farmland classification: Not prime farmland
Map Unit Composition
Atkins and similar soils:90 percent
Estimates are based on observations, descriptions, and transects of the map unit.
Description of Atkins
Setting
Landform: Depressions on flood plains, backswamps on flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread
Down-slope shape: Concave
Across-slope shape: Concave
Parent material: Alluvium derived from sandstone and shale
Typical profile
Oe - 0 to 3 inches: moderately decomposed plant material
A - 3 to 10 inches: loam
Bg - 10 to 25 inches: silty clay loam
Cg1 - 25 to 38 inches: silty clay loam
Cg2 - 38 to 62 inches: very gravelly sandy loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Poorly drained
Runoff class: Negligible
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.06 to 1.98 in/hr)
Depth to water table: About 0 to 12 inches
Frequency of flooding: Frequent
Frequency of ponding :Frequent
Available water supply, 0 to 60 inches: Moderate (about 8.1 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 6w
Hydrologic Soil Group: C/D
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Hydric soil rating: Yes
12B—Derroc cobbly sandy loam, 0 to 5 percent slopes, occasionally flooded
Map Unit Setting
National map unit symbol: kdn9
Elevation: 1,720 to 3,660 feet
Mean annual precipitation: 26 to 52 inches
Mean annual air temperature: 52 to 55 degrees F
Frost-free period: 145 to 175 days
Farmland classification: Not prime farmland
Map Unit Composition
Derroc and similar soils:80 percent
Estimates are based on observations, descriptions, and transects of the map unit.
Description of Derroc
Setting
Landform: Flood plains
Landform position (three-dimensional):Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium derived from sandstone, limestone, shale, and quartzite
Typical profile
H1 - 0 to 8 inches: cobbly sandy loam
H2 - 8 to 35 inches: very cobbly sandy loam
H3 - 35 to 62 inches: extremely cobbly loamy sand
Properties and qualities
Slope:0 to 5 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):High to very high (1.98 to 19.98 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 4.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 2s
Hydrologic Soil Group: A
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Hydric soil rating: No
3—Craigsville cobbly sandy loam, 0 to 5 percent slopes, frequently flooded
Map Unit Setting
National map unit symbol: 2qm0n
Elevation: 980 to 4,210 feet
Mean annual precipitation: 35 to 51 inches
Mean annual air temperature: 50 to 55 degrees F
Frost-free period: 135 to 180 days
Farmland classification: Not prime farmland
Custom Soil Resource Report 53
Map Unit Composition
Craigsville and similar soils:90 percent
Estimates are based on observations, descriptions, and transects of the map unit.
Description of Craigsville
Setting
Landform:Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium derived from sandstone and shale and/or quartzite and/or siltstone and/or metasedimentary rock
Typical profile
Oi - 0 to 1 inches: slightly decomposed plant material
A - 1 to 4 inches: cobbly sandy loam
Bw - 4 to 36 inches: extremely cobbly sandy loam
C - 36 to 63 inches: extremely cobbly sandy loam
Properties and qualities
Slope:0 to 5 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):High to very high (1.98 to 19.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: Frequent
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 4.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 2w
Hydrologic Soil Group: A
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Hydric soil rating: No
39A—Speedwell loam, 0 to 3 percent slopes, occasionally flooded
Map Unit Setting
National map unit symbol: kfdz
Elevation: 1,380 to 3,050 feet
Mean annual precipitation: 38 to 48 inches
Mean annual air temperature: 52 to 55 degrees F
Frost-free period: 160 to 190 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Speedwell, loam, occasionally flooded, and similar soils:85 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Speedwell, Loam, Occasionally Flooded
Setting
Landform: Flood plains
Landform position (two-dimensional):Toeslope
Landform position (three-dimensional):Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium derived from limestone, sandstone, and shale
Typical profile
H1 - 0 to 11 inches: loam
H2 - 11 to 65 inches: loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 11.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 1
Hydrologic Soil Group: B
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Forage suitability group: Fertile Soils (G128XM003VA)
Other vegetative classification: Fertile Soils (G128XM003VA)
Hydric soil rating: No
2A—Atkins loam, 0 to 3 percent slopes, frequently flooded
Map Unit Setting
National map unit symbol: kffg
Elevation: 1,340 to 3,640 feet
Mean annual precipitation: 38 to 48 inches
Mean annual air temperature: 52 to 55 degrees F
Frost-free period: 160 to 190 days
Farmland classification: Not prime farmland
Map Unit Composition
Atkins, loam, frequently flooded, and similar soils:75 percent
Estimates are based on observations, descriptions, and transects of the map unit.
Description of Atkins, Loam, Frequently Flooded
Setting
Landform: Backswamps on flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread
Down-slope shape: Concave
Across-slope shape: Concave
Parent material: Alluvium derived from limestone, sandstone, and shale
Typical profile
H1 - 0 to 4 inches: loam
H2 - 4 to 28 inches: loam
H3 - 28 to 65 inches: gravelly loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Poorly drained
Runoff class: Negligible
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.06 to 1.98 in/hr)
Depth to water table: About 0 to 12 inches
Frequency of flooding: Frequent
Frequency of ponding: Frequent
Available water supply, 0 to 60 inches: Moderate (about 8.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 6w
Hydrologic Soil Group: B/D
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Forage suitability group: Hydric Soils (G128XM005VA)
Other vegetative classification:
4—Pope fine sandy loam, 0 to 3 percent slopes, occasionally flooded
Map Unit Setting
National map unit symbol: 2mr98
Elevation: 840 to 3,330 feet
Mean annual precipitation: 35 to 51 inches
Mean annual air temperature: 50 to 55 degrees F
Frost-free period: 135 to 180 days
Farmland classification: All areas are prime farmland
Custom Soil Resource Report 54
Map Unit Composition
Pope and similar soils:85 percent
Estimates are based on observations, descriptions, and transects of the map unit.
Description of Pope
Setting
Landform: Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium derived from sandstone and shale and/or quartzite and/or siltstone and/or metasedimentary rock
Typical profile
A - 0 to 8 inches: fine sandy loam
Bw - 8 to 45 inches: gravelly sandy loam
C - 45 to 65 inches: very gravelly loamy sand
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.57 to 5.95 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 5.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (non-irrigated): 1
Hydrologic Soil Group: A
Ecological site: F128XY519WV - Mesic Floodplain Alluvium
Hydric soil rating: No
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